Nitric Acid (HNO3) has a Ka value of ∞ (no finite equilibrium constant, so it’s a strong acid). Calculate the pH of a solution that is 0.00298 M nitric acid.
The Correct Answer and Explanation is :
itric acid (HNO₃) is classified as a strong acid, meaning it dissociates completely in aqueous solutions.his complete dissociation implies that the concentration of hydrogen ions (H⁺) in the solution is equal to the initial concentration of the nitric acid.he pH of a solution is determined by the negative logarithm (base 10) of the hydrogen ion concentration:
[ \text{pH} = -\log[\text{H}^+] ]
iven a 0.00298 M solution of nitric acid, the concentration of hydrogen ions [H⁺] is 0.00298 M.pplying the pH formula:
[ \text{pH} = -\log(0.00298) ]
alculating this yields:
[ \text{pH} \approx 2.53 ]
herefore, a 0.00298 M solution of nitric acid has a pH of approximately 2.53.
Explanation:
he strength of an acid is determined by its acid dissociation constant (Kₐ).trong acids, like nitric acid, have very large Kₐ values, indicating that they ionize completely in solution.his complete ionization means that for every mole of HNO₃ dissolved in water, one mole of H⁺ ions and one mole of nitrate ions (NO₃⁻) are produced.
n the case of a 0.00298 M nitric acid solution, the concentration of H⁺ ions is directly equal to the acid’s concentration, which is 0.00298 M.he pH scale is a logarithmic representation of hydrogen ion concentration, defined as the negative base-10 logarithm of the H⁺ concentration.his logarithmic scale allows for a more convenient expression of the wide range of hydrogen ion concentrations found in various solutions.
y substituting the known H⁺ concentration into the pH formula:
[ \text{pH} = -\log(0.00298) ]
e find that the pH is approximately 2.53.his value is consistent with the acidic nature of the solution, as pH values less than 7 indicate acidity.
t’s important to note that while strong acids are assumed to dissociate completely, this assumption holds true for dilute solutions.n highly concentrated solutions, factors such as ion pairing and activity coefficients can affect the degree of dissociation, but these effects are negligible at the given concentration.
n summary, the pH of a solution is a measure of its hydrogen ion concentration.or strong acids like nitric acid, which dissociate completely in dilute solutions, the pH can be directly calculated from the molarity of the acid using the negative logarithm.hus, a 0.00298 M solution of nitric acid has a pH of approximately 2.53, reflecting its acidic properties.